I can never get ahead on Lessons. What am I doing wrong?

If you look at your App Settings, there should be a setting for lesson order. Make sure that is still set to: level, then type.

After you level up, radicals and kanji and vocab for the new level get unlocked, but you also still have vocab lessons from the previous level in your queue. Using the above setting will ensure you only get the previous level vocab, until you have gone through them all, and reach the radicals for the current level.

Before I started using @seanblue’s Lesson Filter userscript, I would play around with this setting, by changing the setting to random, after I finished the radical lessons. I like to mix the kanji up with the vocab.